Abstract: To meet the need of studying the difference of isotope effects for zirconium deuteride and tritide desorption, desorption p-t curves of zirconium deuteride and tritide were investigated at 775-875℃ by using the method of the reaction rate analysis in a constant volume system. The desorption rate constants of zirconium deuteride and tritide at different temperatures were determined. The rate of desorption is augmentable along with the increase of temperature and the equilibrium pressure of reaction is increased too. The activation energy of desorption for zirconium deuteride and tritide are （40.1±0.8）kJ/mol and （57.7±1.6）kJ/molrespectively. The desorption activation energy value of zirconium tritide is higher than that of zirconium deuteride and so there are remarkable kinetic isotope effects for desorption.